Instantaneous velocity question?

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Homework Help Overview

The discussion revolves around a statement from a physics PDF regarding the equation x=0.08t³, which describes the motion of a car. Participants express confusion about the origin of this equation and its context within the material.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question how the equation x=0.08t³ was derived and whether it is simply an illustrative example. There is also a discussion about the phrasing "centered at 4.0 s" in relation to a table of values, with suggestions for clearer wording.

Discussion Status

The conversation is ongoing, with some participants providing insights into the phrasing and context of the material. There is no explicit consensus, but clarification on certain terms has been offered.

Contextual Notes

Participants note that the equation appears without derivation in the text, leading to questions about its validity and the clarity of the accompanying explanations.

Saitama
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Homework Statement


The problem is that i am having a doubt in a statement given in the pdf below:-

http://ncertbooks.prashanthellina.com/class_11.Physics.PhysicsPartI/ch-3.pdf

On page number 6, a line is written "For the graph shown in Fig. 3.6, x=0.08 t3." I am not able understand how this x=0.08t3 came out? :confused:

Homework Equations


The Attempt at a Solution

 
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Pranav-Arora said:
On page number 6, a line is written "For the graph shown in Fig. 3.6, x=0.08 t3." I am not able understand how this x=0.08t3 came out? :confused:

Hi Pranav-Arora! :smile:

It is an example.
x=0.08 t3 was not derived anywhere.
It was taken as an example to illustrate the theory.

Btw, your link did not work as is. :wink:
 
Last edited:
I like Serena said:
Hi Pranav-Arora! :smile:

It is an example.
x=0.08 t3 was not derived anywhere.
It was taken as an example to illustrate the theory.

Btw, you link did not work as is. :wink:

Thanks for your reply! :smile:
And the link works properly!
 
Pranav-Arora said:
the link works properly!

Right! Now it does!
Did you change it? :confused:
 
I like Serena said:
Right! Now it does!
Did you change it? :confused:

No, i didn't change it! :wink:
 
I agree that the equation does seem to appear out of nowhere, so it's probably just a given that the equation x=0.08t^3 describes the car's motion. The author probably should have pointed this out. It doesn't really follow that this is the case from any of the text that precedes it.

HTH
 
After the line, "For the graph shown in Fig. 3.6, x=0.08 t3." it is written that "Table 3.1 gives the value of Δx/Δt calculated for Δt equal to 2.0 s, 1.0 s, 0.5 s, 0.1 s and 0.01 s centred at t = 4.0 s."

What does it mean by "centered at 4.0s"?
 
Pranav-Arora said:
What does it mean by "centered at 4.0s"?

It would have been better worded if they had said "relative to t=4.0 s".

In Fig 3.6 you can see they have taken t=4.0 s as point P, relative to which the example is worked out.
In the table they're showing delta t's that are relative to t=4.0 s.
 
I like Serena said:
It would have been better worded if they had said "relative to t=4.0 s".

In Fig 3.6 you can see they have taken t=4.0 s as point P, relative to which the example is worked out.
In the table they're showing delta t's that are relative to t=4.0 s.

Thanks! :smile:
I got it.
 
  • #10
No more questions? :confused:

I would have expected another one by now! :smile:
 
  • #11
I like Serena said:
No more questions? :confused:

I would have expected another one by now! :smile:

Yes, because i left this topic for a few days to complete the MIT lectures on Calculus. :wink:
 

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